Actor William H. Macy at The James Hotel August 31, 2012. (Zbigniew Bzdak/ Chicago Tribune)

There are plenty of actors in Hollywood who are notoriously difficult to work with on set, but William H. Macy has never appeared to be one of them — or so it seemed. The “Fargo” and “Seabiscuit” actor, nicknamed “Howdy Doody” by director David Mamet for his resemblance to the children’s TV show puppet, claims he wasn’t a very friendly co-worker early on in his 30-plus-year career.

“I was an (expletive),” Macy said in August at The James Hotel. “When you’re young, you excuse your behavior: ‘I just want this to be great. I’m telling the truth. I’m not going to apologize for that.’ As you grow older, you learn not to fight every battle. I was guilty of that. I wish I had taken a chill pill earlier in my life.”

Macy said he simply grew out of that stage in his life. Now 62 and starring in “The Sessions,” which opens in theaters Friday, Macy believes he has “mellowed” and learned not to take life so seriously. It’s part of an aging process, which he thinks about a lot these days.

“I want to grow older gracefully,” Macy said. “I think about it a lot. I don’t want to be one of those people who jokes about their age. I think the key to life is enjoying what you’re doing right now. The good times — you can’t hang on to them but you can relish them. And the bad times — you’ve got to let them go.”

In “The Sessions,” which is based on a true story,. Macy plays Father Brendan, a Catholic priest, who befriends a parishioner and writer named Mark O’Brien who has polio and is confined to an iron lung. When O’Brien says he wants to lose his virginity with the help of a sex surrogate (played by Helen Hunt), Macy’s character decides to lends his is support.

Macy admitted he became emotional when watching the film for the first time. “I wept,” he said. “The film tells the story of something fundamental. This guy got dealt a bad hand at birth, and yet he was relentless and optimistic and lived life as fully as he possibly could. Everyone wants to know intimacy. It’s a huge part about what it means to be alive. … I also cry a lot. I cry at commercials.”

Macy’s character can be described as a “hip” priest. He wears a bandanna outside of church and in one scene brings a six-pack of beer over to O’Brien’s apartment. While Macy didn’t grow his hair out specifically for this portrayal, he said his long mane added to the role.

“It was great for the character — I’ve got a bunch of hair,” said Macy, who seems to get asked about his hair during every interview. “I got lucky in the hair department. My wife really digs it, and that’s the most important thing.”

Macy’s hair looks a bit more unkempt on Showtime’s “Shameless,” which is based in Chicago and films its exterior scenes here. He plays Frank Gallagher, an alcoholic father and con artist. The third season of “Shameless” premieres Jan. 13.

“I love having a job,” Macy gushed. “I love the continuity of it. I love my trailer, my cast, this character. I love that I get to act a lot. I get to act sometimes every day.

“I look back on all this, and it’s been a grand trip. I like where I am now.”